Ion Selective Membrane Electrodes for the Determination of Xylometazoline Hydrochloride in Rabbit Aqueous Humor using 2-Hydroxy Propyl β-cyclodextrin and Calix[6]arene as Ionophores

Three novel Xylometazoline Hydrochloride (XYLO) selective electrodes were investigated with Dioctyl phthalate (DOP) as a plasticizer in a polymeric matrix of polyvinyl chloride (PVC). Sensor 1 was fabricated using Phosphomolybdic acid (PMA) as an anionic exchanger without incorporation of an ionophore. Sensor 2 used 2-hydroxy propyl -cyclodextrin (hp-CD) as an ionophore while sensor 3 was constructed using calix[6]arene as an ionophore. Linear responses of XYLO within the concentration ranges of 10−4 to 10−2, 10−5 to 10−2 and 10−5 to 10−2 mol L−1 were obtained using sensors 1, 2 and 3, respectively. Nernstian slopes of 49.78, 56.21 and 46.20 mV/decade over the pH range of 5–9 for sensors 1, 2 and 5-7 for sensor 3 were observed. The selectivity coefficients of the developed sensors indicated excellent selectivity for XYLO. The utility of 2-hydroxy propyl -cyclodextrin and calix[6]arene as ionophores had a significant influence on increasing the membrane sensitivity and selectivity of sensors 2 and 3 compared to sensor 1. The proposed sensors displayed useful analytical characteristics for the determination of XYLO in bulk powder, different pharmaceutical formulations, and biological fluids (Rabbit aqueous humor) and in the presence of its degradation product (2, 6- dimethyl-4-tertbutyl- phenylacetic acid) and thus could be used as stability-indicating method.